Since an electrode of an organic device serves as a contact point where an organic compound which indicates a function of the device is connected with an inorganic compound such as a wiring, the electrode is very important and various refinements are applied. For example, as an electron injection electrode of an organic EL element, a technology of doping a metal such as an alkali metal having low work function is effective (See Patent Literature 1). As to the technology, a metal is made to serve as a donor, and the metal and an organic compound composes a charge-transfer complex; thus, electron injection properties are improved. Accordingly, the ratio of the metal and the organic compound is supposed to be optimum at about 1:1 in molar ratio (See Non-patent Literature 1).
[Patent document 1] Japanese Patent Laid-Open No. 10-270171
[Non-patent Literature] Applied Physics letters, “Bright Organic Electroluminescent Devices Having Metal-Doped Electron-Injecting Layer” America, Institute of Physics, November 1998, Vol. 70, No. 2, pp. 152-154, J. Kido et al.
An electrode for an organic device described above is manufactured by a method in which an organic compound and a metal are respectively evaporated by resistance heating, and mixed and deposited in the gas phase (what is called a co-evaporation method). On this occasion, the ratio of the organic compound and the metal is monitored with crystal oscillator to be monitored by weight. In general, most of organic compounds used for the organic device have molecular weight of more than hundreds (for example, the molecular weight of Alq used in the Non-patent Literature 1 is 459). Meanwhile, atomic weight of metal is extremely small compared to that (for example, the atomic weight of Li is 7). Accordingly, in the case where the ratio of the metal and the organic compound is about 1:1, the ratio of the metal by weight is very low.
Hence, in the case of forming an electrode for an organic device so that a metal and an organic compound compose a charge transfer complex, it has been difficult to manufacture a stable and uniform device because of bad controllability of the deposition rate of the metal. Further, in particular, most of semiconducting or conductive inorganic compounds (semiconducting/conductive oxide and the like) other than metal has low vapor pressure and are difficult to evaporate by resistance heating; therefore, an electrode for an organic device in which those are mixed with the organic compound could not be formed.